Reflex camera having reflecting finder system



July 4,v 1950 A, B HARROTT 2,513,861

REFLEX CAMERA HAVING REFLECTING FINDER SYSTEM Filed April 29, 1947 2Sheets-Sheet l l l! f Q] a /f I I 7 A| 6 I( /f//f l July 4,l 1950 A. B.HARRQTT 2,513,861

mme cAMERA HAVING REFLECTING FINDER SYSTEM Filed April 29, 1947 2Sheets-Sheet '2 Z zf 6 /4 f @Wm/MMM Patented July 4, 1950 UNITED REFLEXCADIERA HAVING REFLECTING FINDER SYSTEM Alfred B. Harrott, Rochester, N.Y.

Application April 29, 1947, Serial No. 744,671

(Cl. 95-4v2) 1 claim. l

My invention relates to cameras, particularly to a focusing arrangementfor use with a camera of the reflex type.

In the basic type of reliex camera, the objective lens projects an imageupon a ground glass screen. In the older type of camera, the image wasprojected upon the vertical screen mounted directly behind the lens. Incameras of later design, variants are employed whereby a mirror inclinedat an angle, generally 45 degrees, erects the image upon the glassscreen, usually placed horizontally, and it is viewed from the top ofthe camera.

My device employs the conventional reflex method, using a swingingmirror and perpendicular ground glass screen to receive and reflect theimage, but by a unique grouping of lens and mirrors, the image whenretracted through the screen is picked up and reflected through a seriesof iixed mirrors, and may be viewed erect through an aperture in theback of the camera adjacent the conventional vievv lnder.

It is an important object of my invention to provide a range iindingdevice for a camera of the reflex type which will alloviT a magniiiedinspection of part or all of the image reflected on the ground glassscreen from a position behind the camera.

It is another important object of my invention to provide a device ofthe character described having a focusing system in which only the lensand mirror on which the lens projects the image are movable.

It is a further object of the invention to pro vide a device of thecharacter described in which either a combination of prisms or a systemof Xed lens and mirrors may be used in associa* tion with a swingingmirror positioned in the exposure chamber of the camera to magnify andorient the image projected on said swinging mirror by the objective lensof the camera.

It is a still further object. of my invention to provide a device of thecharacter described in which the image retracted through the groundglass screen is quite brilliant, and after the refracted image isreected it appears erect in stead of laterally reversed, the saidreflected image being observable through an aperture in the back of thecamera.

It is another object ol my invention to provide It is a still furtherobject of my invention to provide a device of the character describedwhich operates through the single objective lens of the camera, isitsellC an integral part of the camera, and permits focusing with anuncalibrated lens.

Other objects and advantages of the invention will become apparentduring the course of the following specification, and accompanyingdrawings, forming part of the specification, in which like numerals areused to designate like parts throughout the specicaticn and drawings.

In the drawings:

Figure 1 is a plan view of the inside of a camera embodying myinvention, taken substantially on the line l-l of Figure 2,

Figure 2 is a sectional view of the same, taken substantially on theline 2--2 of Figure 1,

Figure 3 is a vievv similar to Figure l, prisms being substituted forthe iixed lens and mirrors shown in Figure l, taken on the line 3--3 ofFigure 4, and

Figure 4 is a sectional view of the same, taken substantially on theline 4-4 of Figure 3.

Referring now in detailvto the drawings, particularly to Figures 1 and2, the numeral 6 designates a camera arranged with interior partitions'l dividing the interior of the body into an exposure chamber 8 andspaced apart lm chambers 9 at the opposite ends of the said camera inwhich the respective spools of a roll lm l0 are mounted, there being acommunicating passage il therebetween through which the lm IB is drawnin the usual manner, for'successive exposure of individual portionsthereof to an objective lens i2, having means for focusing, mounted onthe front of the camera in any conventional manner. The camera may alsobe provided with the usual view iinder window i3 through Which the sceneto be photographed may be located, and the usual conventional curtainmeans 5i) for cutting off light admitted into the exposure chamber whenthe lens is open for focusing the image on a screen, to preventpremature exposure of the said nlm. Since all f of these features areold and Well known in the art, and form no part of myv invention, theyneed not be further described.

A perpendicular ground glass screen i4 is permanently mountedtransversely of the camera body from the front interior wall thereof toa portion of the partition 'i deiining the v fall of the passage ll andadjacent one side of the lens I2, and is adapted to receive an imagereflected thereon by a mirror l5 to which the said image is projected bythe lens l2. The mirror l5 lis yfixed mirrors.

3 pivotally mounted, as at I6, for swinging motion relative to the saidscreen, there being a stop II to limit said motion outwardly from thesaid screen to an angle of 45 degrees carried on the floor of saidexposure chamber. The said mirror I5 may be swung from and toward thesaid screen I4 by means of a knurled knob I8 associated with said pivot,or by any other convenient attachment.

The optical grouping of my focusing system comprises a converging lensI9 suitably mounted in any convenient manner adjacent the side of thescreen I4 opposite the mirror I5 in the space dened by the said screenand the adjacent partition 1, and a plurality of fixed mirrors 20, 2i,and 22, mounted as shown, to reflect the image retracted through thescreen I4 a total of 180 degrees. The mirror 22 is mounted adjacent afocusing window 23 on the back of the camera, through which a clear viewof the image re fracted by the screen I4 may be viewed from outside thecamera. I also provide a clear-glass covered opening 24 in the top ofthe camera yshown in the respective figures.

through which a laterally reversed image may be seen when for anyreason, such as taking candid shots, observation through the rear mightbe inconvenient.

To focus the camera, the mirror I5 is swung on its pivot until stoppedby the stop member posing it, and an image of the scene'to be pho- I.

tographed is projected onto the mirror I5, and

is reiiected therefrom to the adjacent surface of the screen I4. Thereected image is then refracted through the said screen, to be picked upvupon emergence through the opposite side of the screen by theconvergent lens I9, mounted in the said exposure chamber adjacent thescreen, as

'hereinbefore described. The image is inverted as it passes through thelens I9, the inverted image `being picked up and reected by thesuccessive fixed mirrors 20, 2|, and 2'2, until, when the said imagereaches the mirror 22, visible from outside the camera, it is againerect, the image having been reflected a total of 180 degrees by the Aspointed out, the image may also be observed from the top of the camerathrough the window 24. Ihe camera may now be brought into an exact focusby the focusing mechanism associated with the lens I2 to show a sharpand distinct image. 'Ihe lens is now closed, the shutter componentsopened, the mirror I5 swung on its pivot to clear the path' between thelens I2 and the lm I 0, and the camera is ready to snap a clear anddistinct picture of the scene.

Referring now to the embodiment of Figures 3 and 4, it will be notedthat the structure of the camera, including the screen I4, the mirrorI5, stop I'I, means 30, and focusing window 23, is identical with theembodiment illustrated in Figures 1 and 2. The lens I9, the xed mirrors20, 2|, and 22, and the opening 24 have been eliminated.

I have replaced the lens and xed mirrors by a pair of prisms, includinga lens-surfaced erecting prism suitably mounted in the space between thescreen I4 and the adjacent partition 1, arranged to pick up the imageretracted through the said screen I4 as hereinbefore explained, the saidimage now being reflected through the prism 25 without distortion, to beI have described my invention in the forms best known to me at thistime. It is to be understood, however, that changes in the shape andarrangement of the parts may be made within the scope of the subjoinedclaim without departing from the spirit of the invention.

Having thus described the invention, I claim:

A reflex type camera, comprising a rectangular casing including frontand rear sides, ends, a top and bottom, vertically-disposed L-shapedpartitions secured to the front side and extending near the rear sideand inwardly of the ends forming an inner rectangular exposure chamber,end lm chambers and a longitudinal film passage, an adjustable objectivelens mounted upon the front side near its longitudinal center and nearthe bottom, a 45 degree vertical mirror arranged within the exposurechamber rearN wardly of the objective lens and near the bottom, themirror being pivotally connected at its near vertical edge to the topand bottom of the casing, a rod secured to the mirror and extendingrotatably through the top of the casing for turning the mirror, avertically disposed ground glass screen disposed within the exposurechamber and secured to the front side and one L. shaped partition andspaced laterally of the objective lens, a converging lens spacedlaterally outwardly of the screen near the bottom and secured to thefront side and said L-shaped par tition, a 45 degree inclined mirrorplate disposed laterally outwardly of the converging lens and secured tothe bottom and to said partition, a second 45 degree inclined mirrorarranged above the last-named inclined mirror plate and ob jective lensand secured to the top of the casing at its top edge only, a second 45degree vertical mirror plate secured to the top of the casing at its topedge only and arranged above and at right angles to the first-namedvertical mirror, and a window in the rear side near the top and inalignment with the last-named mirror.

ALFRED B. HARROTT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,484,584 'Iauen Feb. 19, 19242,057,198 Marcussen Oct. 13, 1936 2,256,517 Cohen Sept. 23, 19412,284,562 Dittman May 26, 1942 2,442,327 Soreny May 25, 1948 FOREIGNPATENTS Number Country Date 489,125 Great Britain July 20, 1938 OTHERREFERENCES Ser. No. 304,702, Kuppenbender, (A. P. 0.), published May 4,1943 (abandoned).

